It's Not Too Difficult: A Plea to Resurrect the Impossibility Defense

50 Pages Posted: 23 Jun 2014 Last revised: 6 Dec 2015

See all articles by Ken Levy

Ken Levy

Louisiana State University, Baton Rouge - Paul M. Hebert Law Center

Date Written: February 16, 2015


Suppose you are at the gym trying to see some naked beauties by peeping through a hole in the wall. A policeman happens by, he asks you what you are doing, and you honestly tell him. He then arrests you for voyeurism. Are you guilty? We don’t know yet because there is one more fact to be considered: while you honestly thought that a locker room was on the other side of the wall, it was actually a squash court. Are you guilty now?

Probably. You might argue that your scopophiliac ambition was impossible to satisfy given that you were peeping into a squash court, not a locker room. But this “Impossibility Defense” would fail because most jurisdictions follow the very influential Model Penal Code (MPC), which says that what is important about attempt is not the likelihood of success but rather what was going on in your head. You tried to peer into a locker room with the intention of seeing some nudity; that is enough for culpability. The fact that you were mistaken about the location does not exonerate you.

But now suppose that the particular jurisdiction you are in does not criminalize voyeurism. While most people think that voyeurism is just plain wrong, if not disgusting, the legislature just never got around to drafting a statute against it. Are you guilty now? The answer is no. But you might just be out of luck and convicted anyway.

The reason for this strange conclusion is that most jurisdictions have followed the Model Penal Code in yet another respect: along with the MPC’s “subjectivist” emphasis on what is in your head, they have followed the MPC’s lead in abolishing the Impossibility Defense entirely. As a result, people who believe that they are breaking laws when they really are not may still be subject to arrest, prosecution, and conviction respectively by police, prosecutors, and judges/juries merely if all three parties regard your conduct — especially your trying to violate a law that you mistakenly believed in — as morally reprehensible. The best, if not only, defense against this charge is the Impossibility Defense, but — again — most jurisdictions have decided to make this defense unavailable to defendants.

Depriving eligible defendants of the Impossibility Defense is unjust. It violates one of the most basic principles of criminal justice: the legality principle. The legality principle says that there cannot be just punishment without a crime, and there should not be a crime without an explicit law designating it as such. So you cannot be charged with, and convicted of, attempted voyeurism if voyeurism, reprehensible as it may be, was not explicitly prohibited at the time that you made the attempt.

If we believe in the legality principle, then we must restore the Impossibility Defense. Without the latter, too many defendants are being — and will continue to be — punished for attempts to perform acts that were not themselves illegal but which various parties in the criminal justice system (except the legislature) thought should be illegal based on their extralegal, moral prejudices.

In addition to the MPC, the principal obstacle to resurrecting the Impossibility Defense is a good deal of conceptual confusion that permeates relevant cases and scholarship. Too many courts and academics have conflated “factual impossibility” with “legal impossibility” and have fallaciously inferred “hybrid impossibility” from “hybrid mistakes” (that is, legal mistakes that derive from factual mistakes). One of the principal goals of this Article, then, is to clear up all of this confusion. I will explicate in the simplest possible terms (a) the difference between factual impossibility and legal impossibility, (b) why only legal impossibility qualifies as exculpatory, and (c) why hybrid impossibility simply does not exist.

Keywords: Impossibility defense, attempt, mistake of fact, mistake of law, legality principle, factual impossibility, legal impossibility, hybrid impossibility, intrinsic impossibility, Model Penal Code, voodoo

Suggested Citation

Levy, Ken, It's Not Too Difficult: A Plea to Resurrect the Impossibility Defense (February 16, 2015). New Mexico Law Review, Vol. 45, No. 1, 2014, Available at SSRN:

Ken Levy (Contact Author)

Louisiana State University, Baton Rouge - Paul M. Hebert Law Center ( email )

420 Law Center Building
Baton Rouge, LA 70803
United States

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